Filtering devices of the above-mentioned type are typically inserted in the gas supply system of the engine between a pressure reducing valve and a set of electrically controlled injectors, to which the gas is supplied at pressure values (produced by the reducing valve) which are normally close to atmospheric pressure (for naturally aspirated engines) or a few bar (for injection type engines). These filtering devices, which are typically provided with cartridge type filtering elements, are arranged upstream of the set of electrically controlled injectors for the protection thereof in order to remove any impurities from the combustible gas.
In known systems for supplying gas to engines, in order to obtain correct electronic management of the fuelling, it is necessary to acquire a series of signals, the most relevant of which are the gas injection temperature and pressure, in the set of injectors, the absolute pressure present in the engine inlet manifold, the signal relating to the rotational revolutions of the engine and the supply times of the injectors. In relation to the above-mentioned pressure and temperature signals, a first known solution provides for the use of distinct and separate sensors which are mutually independent. One example of such a construction provides for the individual injection temperature and pressure sensors to be positioned in the set of injectors and the sensor for absolute pressure at the manifold to be positioned in the electronic management module, in which the signal for the pressure present in the manifold is introduced. One of the greatest limitations encountered in this known solution relates to the fact that the above-mentioned sensors involve separate and distinct components which makes the installation thereof more complex, in addition to involving higher overall costs for manufacture and greater complexity of the layout of the pipes and electrical connections (in order to supply the sensors and acquire the signals from the respective transducers) provided for connecting the entire system. The higher level of complexity and difficulty is obviously reflected in the steps for installing and maintaining the system, with the additional risk of incorrectly installing the components.
In order to partially overcome the disadvantages set out, the prior art has provided technical solutions in which the gas injection pressure sensor and the sensor for the absolute pressure at the manifold are combined in a single component; however, such solutions only partially solve the above-mentioned problem.
There are also known solutions in which the injection temperature and pressure sensors are combined in a single component which is able to be associated, by means of suitable mutual fixing means, with the body of the gas filtering device provided in the system. This solution also has some limitations, including the fact that it is still necessary to provide a separate and distinct sensor for detecting the pressure at the manifold, which in some known solutions is accommodated in the electronic management module of the system, also involving the limitations set out above.